Prós
From the corporate culture to the breadth of projects available, nearly every aspect of life at NI is exciting. I have yet to meet or work with anyone who isn't passionate about their work and team. In the R&D group, the engineers are always in constant communication with management, and the work atmosphere makes it so no one is ever afraid to voice opinions or provide constructive feedback. Also, in the 30+ years of NI's history, it has yet to go through any round of layoffs.
Contras
The lack of layoffs does mean NI has to tighten the belt elsewhere when things get financially tough - specifically employee salaries. NI's been known to come in lower on salaries than other companies, but their outlook is that they want to attract employees who are committed to working in a stable environment. While admirable, that's the one point keeping me from rating NI as 5 stars.